from The Century Dictionary and Cyclopedia

Exhibiting harmony or being in harmony; having parts, forms, relations, or proportions properly accordant each with the others, so that all taken together constitute a consistent or an esthetically pleasing whole; also, being in harmony or concord with something else; congruous.

Specifically, in music, concordant; consonant; symphonious; agreeable to the ear. See harmony.

Marked by harmony in action or feeling; acting or living in concord; peaceable; friendly: as, harmonious government; a harmonious family.

DOUGLAS DEVOS : This was based on the world-view perspective that subject expert Larry Summers set out: Either we're going to have tit-for-tat discussions on very short-term issues every time something pops up or we're going to form a long-term harmonious relationship.

It is the first duty of federal economic policy to maintain harmonious and trustful relations with the nations of the West so that our markets will be secured by our own good faith and scrupulous respect for the rights of others and from whom, in turn, we can demand the same.

Instead of divided and controversially-minded institutions we have a group of colleges working together in harmonious relations, realising each its own individuality and yet each contributing to the welfare of the University as a whole.